title: Extensor retinaculum of the wrist: gross anatomical correlation with MR imaging after ultrasound-guided tenography with emphasis on anatomical features in wrist dorsiflexion responsible for tendon impingement.
abstract: OBJECTIVE
  To demonstrate the anatomy of the extensor retinaculum (ER) of the wrist using gross anatomical correlation with magnetic resonance (MR) imaging before and after ultrasound-guided tenography in four different positions, emphasizing the morphological appearance of the ER that occurs with dorsiflexion of the wrist to define the nature of extensor tendon impingement in athletes who perform repetitive wrist dorsiflexion.
  
  
  METHODS
  Institutional policies were followed regarding cadaver use. Ten upper extremities were harvested from fresh cadavers. MR imaging before and after ultrasound-guided tenography of the wrist was performed, followed by gross anatomical correlation. Two radiologists interpreted the MR images and sections by consensus for the anatomical landmarks of the ER, and morphological changes occurring during dorsiflexion of the wrist were analyzed and measured.
  
  
  RESULTS
  The ER of the wrist appeared as a band of low signal intensity on T1- and PD-weighted images. Because of its orientation, axial images were best suited to depict the ER anatomy; specifically, localization of the bony landmarks and the septal attachments. On sagittal images, a consistent appearance of the ER was seen: appearing with fusiform morphology in the neutral position, and becoming shortened and thickened at the abutment point where the extensor tendons of the fourth compartment had a curved excursion during dorsiflexion. The width and thickness of the ER in neutral position averaged 13.56 mm and 1.67 mm respectively. In wrist dorsiflexion, the average width and thickness changed to 8.68 mm and 2.15 mm respectively.
  
  
  CONCLUSIONS
  Magnetic resonance imaging is a useful technique to demonstrate the ER of the wrist, the septal attachments, and morphological changes that occur during dorsiflexion of the wrist, which potentially can lead to impingement of the extensor tendons.
authors.affiliation: Department of Radiology, Division of Musculoskeletal Radiology, University of California, San Diego-UCSD Teleradiology and Education Center, La Jolla, CA, USA, anmassaki@gmail.com.
authors.forename: Alexandre Norio
authors.initials: AN
authors.lastname: Massaki
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Tan
authors.forename: Brady K
authors.initials: BK
authors.lastname: Huang
authors.forename: Eric Y
authors.initials: EY
authors.lastname: Chang
authors.forename: Debra J
authors.initials: DJ
authors.lastname: Trudell
authors.forename: Donald L
authors.initials: DL
authors.lastname: Resnick
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001265:Athletic Injuries / Q000000981:diagnostic imaging / Q000473:pathology*; D002102:Cadaver; D012090:Cumulative Trauma Disorders / Q000000981:diagnostic imaging / Q000473:pathology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D008953:Models, Anatomic; D016059:Range of Motion, Articular; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013223:Statistics as Topic; D013708:Tendon Injuries / Q000000981:diagnostic imaging / Q000473:pathology*; D013710:Tendons / Q000000981:diagnostic imaging / Q000473:pathology*; D014463:Ultrasonography / Q000379:methods; D014954:Wrist Injuries / Q000000981:diagnostic imaging / Q000473:pathology*; D014955:Wrist Joint / Q000000981:diagnostic imaging / Q000473:pathology*